Two-compartment vials in which a lyophilized medication and a solvent are held in complete independence from each other have been in common use for packaging and mixing medications for many years. Such vials are provided with a neck at one end which opens into one of the compartments, and a cap or closure structure is associated with the vial neck. This closure structure must be capable of closing and sealing the vial to prevent contamination of the medication therein. This closure structure must also be easily attached to the vial and capable of efficient and dependable activation when use of the medication is desired, which activation must be accomplished without causing contamination of the medication or of the syringe used for withdrawing it.
In an attempt to accomplish the above objectives, numerous closure structures have been devised which employ a stopper sealingly disposed within the vial neck and partially captivated by a surrounding cap which engages the rim of the vial neck. By depressing the stopper, after release or removal of the cap, the center plug is dislodged from the constriction between the compartments to allow the solvent and medication to be mixed together. This type of closure structure is illustrated in U.S. Pat. No. 4,089,432, owned by the assignee of this application. The closure structure of this latter patent utilizes a sleeve which is associated with the cap and snugly surrounds a protruding portion of the stopper, whereupon this sleeve and protruding portion are both moved into the vial neck during activation, the sleeve portion being joined to a vial mounting ferrule by a frangible connection. However, it is undesirable in some instances to utilize a cap having a frangible connection associated therewith.
In a continuing effort to improve the closure structure associated with such two-compartment vials there has been developed the closure structure disclosed in copending U.S. application Ser. No. 80 740, filed Oct. 1, 1979, now U.S. Pat. No. 4,267,925, also owned by the assignee of this application. This latter application discloses a closure structure wherein the stopper is lockingly engaged to an inner cap sleeve which snugly surrounds the protruding portion of the stopper, which inner cap sleeve is integrally formed with and concentrically surrounded by an outer cap sleeve which lockingly engages the rim on the vial neck. This outer cap sleeve, or skirt, has several locking flanges so that the cap can be depressed during activation of the closure structure to cause a corresponding depression of the stopper, and hence activation of the vial, with the stopper and cap both being locked in their depressed conditions. This closure structure was developed specifically for use on vials having a neck opening which is of the same size, that is diameter, as the adjacent vial compartment, and has operated fairly satisfactorily when used with a large or wide-mouth vial of this type.
However, there still exists a need for a closure structure suitable for use on a conventional two-compartment vial of the type wherein the neck opening is substantially smaller than the adjacent compartment with which it communicates, which closure structure must be capable of efficiently sealing the neck opening while permitting efficient and simple activation of the vial when desired, while at the same time permitting control over the stopper both during and after activation.
One of the problems which has been long experienced with conventional vials of this latter type, that is vials having a neck opening smaller than the adjacent compartment, is the difficulty in retaining control over the stopper both during and after vial activation. Many of the known closure structures have been unsatisfactory in that, during activation of the vial, the stopper has a tendency to pop completely through the neck into the compartment, thereby contaminating the medication. Another difficulty with these conventional structures is the inability to easily remove all of the mixed medication with a syringe due to the protrusion of the depressed stopper part way into the adjacent compartment such that, when the vial is inverted and a syringe inserted through the stopper, a portion of the medication is isolated in the annular space surrounding the depressed stopper and hence can not be easily removed.
Accordingly, it is an object of the present invention to provide an improved closure structure specifically for use on a two-compartment vial of the type having a neck opening at one end which is of substantially smaller diameter than the adjacent compartment. The closure structure involves a cap which surrounds and permits activation of a stopper sealingly seated within the neck of the vial, whereby activation of the stopper is more uniformly achieved while at the same time the stopper and the vial contents are maintained free of contamination. The cap additionally has locking structure associated therewith such that it is fixedly connected to the vial neck when in a nonactivated condition, and is also similarly locked to the vial when in an activated position to permit secure handling of the vial, such as during insertion of a syringe through the stopper, without requiring removal of the cap. The cap, however, does permit limited slidable displacement thereof, and of the stopper, such as a limited withdrawal relative to the vial when in an activated position, to permit access to the entire vial contents. The cap is also securely locked to the stopper both before, during and after activation to insure proper control over the stopper at all times, and to positively prevent the stopper from popping into the enlarged compartment during activation.
In the vial and closure assembly of the present invention, the reduced neck end of the vial has a resilient stopper sealingly seated therein, which stopper has a lower cylindrical portion of larger diameter seated within the neck opening. The stopper also has an upper projecting portion of smaller diameter, which upper portion is surrounded by an annular groove directly adjacent the interface with the larger diameter portion. A one-piece cap surrounds the projecting portion of the stopper and is attached to the rim of the vial. The cap includes concentric inner and outer sleevelike skirts which are radially spaced apart and are joined together by a top wall. The inner skirt has slits extending axially thereof so as to function as a resilient split collet formed by a plurality of resilient fingers which project downwardly from the top wall. The inner skirt snugly surrounds the upper stopper portion and terminates, at its lower free end, in a locking flange which projects into the annular groove to axially lock the cap and stopper together. This inner skirt, when inserted over the upper stopper portion, has the individual fingers thereof suitably resiliently deformed so as to insure that the lower locking flange as associated with each finger snugly snaps into and is resiliently held within the annular groove. This inner skirt is of slightly smaller diameter than the inner diameter of the neck opening, at its free end, so that activation of the vial causes the stopper and inner skirt to be axially slidably inserted into the neck. The neck opening itself is normally of a slight converging taper so that, as the stopper and inner skirt are depressed into the neck opening, the collet defined by the inner skirt more securely grippingly engages the stopper to prevent it from popping into the adjacent compartment. The outer skirt is axially longer than the inner skirt and, at the lower end thereof, has an inner locking flange which resiliently snaps beneath the annular rim of the vial to lock the cap thereto. The outer skirt also has a second locking flange on the inner surface thereof at a location spaced upwardly from the lower edge so that, upon activation, the cap is pushed downwardly so that the vial rim moves past the second locking flange, as permitted by limited resilient deformation of the outer skirt, and snaps into position below the rim to positively lock the depressed cap to the vial. This second locking flange is spaced from the cap top wall by a distance substantially greater than the axial extent of the vial rim such that, when the cap is locked in its depressed or activated position, the cap and stopper can be axially withdrawn a limited extent relative to the vial so that the stopper does not project into the compartment, whereby the medication can be removed therefrom as by use of a syringe.
One of the objects of the improved closure structure according to this invention results from the fact that the inner skirt, namely the split collet, is axially locked to the stopper to create a secure connection therebetween. In addition, this collet is slidably inserted into the vial neck during activation, and a camming relationship exists between the collet and the vial neck so as to increase the gripping of the stopper by the collet to thereby positively axially secure the collet and stopper together, whereby the stopper is positively prevented from popping into the adjacent compartment. This cammed relationship between the collet and the vial neck may be achieved by forming the vial neck with a slight taper, or by providing the collet with a suitable taper.
Another object of this invention is an improved closure structure for a vial, as aforesaid, which due to the positive and secure locking of the stopper to the cap during activation, can be designed to provide for substantially increased stroke of the stopper during activation. In this manner, in situations where the upper compartment is considered oversized and hence contains a larger gas space in view of a smaller quantity of diluent being stored in the compartment, the closure structure can be designed to provide for increased stroke of the stopper such that the latter will project a substantial extent into the upper compartment so as to effect the desired degree of compression to cause efficient dislodgement of the constriction plug. This can be achieved while still retaining the stopper axially secured to the cap such that the stopper does not pop into the compartment.